When the car returned from the grocer's, Henry jumped to his motor-cycle and made his way to the ferry by a route different from the roadster's. He knew he was taking a chance, but he also knew that an accomplice might be trailing the roadster to see if the latter were watched. Henry could follow the spy to the ferry once without arousing much suspicion; but if he were twice seen to do so, his usefulness might be ended. He knew when the ferry-boat would leave its slip and he made his way aboard just before the gate closed.

At once he had a feeling that he had acted wisely. The roadster was again in the forward part of the boat, but this time the driver did not sit placidly looking out over the Bay. He seemed nervous, and every little while turned sharp around and looked about him. Fortunately Henry had concealed his wheel behind a truck and was himself where the spy could not see him. When he noted the spy's restlessness, it flashed into his mind that perhaps the secret service men who had been investigating this spy had not been so careful as they should have been, and that the spy had taken alarm. It was a discouraging thought, for it made Henry's task vastly more difficult. Wisely, therefore, he went into the cabin and sat down. The spy could not see him, and if the latter should stroll about the boat, there was nothing to indicate to whom the motor-cycle belonged.

As the gate opened and the roadster rolled from the ferry-boat, Henry prudently remained well behind it. Up Broadway they went, as fast as the traffic would allow, their pace gradually quickening as they drew away from the congested lower end of the island. The spy drove straight up Broadway. He circled Union Square and continued north. He passed Madison Square and still held to Broadway. Past the shopping district, past Longacre Square, past Columbus Circle, the roadster continued, still on the city's main highway. And at a discreet distance Henry followed.

Now they reached the apartment-house district and slid past block after block of bulky living apartments. And so they continued past Columbia University and down the grade beyond. And here Henry's troubles began. The roadster turned to the left, and Henry knew the driver was making for the Fort Lee ferry.

How should he gain the boat unnoticed? How should he follow, undetected, along the Jersey roads? For after they had crossed the Hudson there would be an end to that concealing traffic that had so far hidden him. He must follow the roadster over lonely roads and yet remain unseen. It was a problem to disturb any one. And it worried Henry not a little. Fortunately dusk was at hand, though the curtaining darkness would not fall for some time.

When the boat reached the Jersey shore, Henry permitted the roadster to get a long start before he went ashore. The spy turned to the right and began to climb the long grade parallel to the river, that would lead him to the top of the Palisades. When the roadster was almost out of sight, Henry mounted his motor-cycle and followed. Even if his quarry should pass completely from view, Henry had no fear of losing him; for the roadster's tracks were plain in the dusty road.

The dusk deepened. As it grew darker, Henry came closer to his quarry, though he kept behind elevations and curves in the road so as still to remain invisible to the driver of the car ahead. Thus they rode for some miles. The country was as Henry had pictured it from his study of the maps. It was sparsely built up, woodlands were on every hand, and the surface of the land was rolling and rock-strewn. It was an excellent place in which to hide—and also an excellent place in which to dodge one's enemies. As Henry thought of this, he drew closer and closer to the car, though still seeking to remain out of sight. As the light failed, and it became difficult to distinguish the marks in the dust before him, Henry drew up so that he could see the roadster, but he discreetly rode close to the side of the highway, where the overhanging trees shadowed him. Even had the roadster's driver been looking straight in his direction, he might never have seen Henry. He was, as he had determined to be, a veritable shadow.

So they rolled northward. At last it grew dark. The driver of the roadster switched on his lights. Now Henry crept still closer. He was in the dark, his lamp unlighted, his motor running silently, and he had no further fear of discovery.

It was well that darkness had come. They had now reached a lonely region where there were few houses. Here, Henry judged, was an excellent place for a secret wireless. And he judged correctly, for hardly had the thought come into his mind before the roadster turned sharply to the left and disappeared. Henry darted up the road. He came at once to what he judged was a large field. Trees no longer bordered the highway on the left side. Dimly Henry saw objects here and there which he thought were boulders and clumps of bushes. He saw no light and stood for a second peering into the darkness, listening with bated breath. Straight ahead of him he heard the faint purring of a muffled motor. He knew that he was not many hundred feet behind it and that this time the car could not escape him. He thrust his motor-cycle into some near-by bushes, first whipping out his metal cane. Then he ran speedily but carefully after the car.

Evidently it was moving cautiously. Henry rapidly drew near to it. When he had come so close that he could see it distinctly, he dropped to a walk and began to look about, trying to see what was around him. Here in the field it was lighter than it had been on the highway under the shadowing trees. The field was, as Henry had guessed, a piece of wild land, grown up with thickets, with great boulders here and there. Directly ahead of him was a clump of bushes. Henry hastened to put them between himself and the car. It was well he did; for hardly had he gotten behind them before the car stopped and the driver got out. The car was not more than two hundred feet distant.